Multiple layer filamentary devices for treatment of vascular defects

ABSTRACT

Braid-balls suitable for aneurysm occlusion and/or parent vessel occlusion/sacrifice (e.g., in treating neurovascular defects) are disclosed. Especially for aneurysm treatment, but also for either one of the aforementioned treatments, the form of the ball is very important. In particular, the density of the device is paramount in applications where braid itself is intended to moderate or stop blood flow—allowing thrombosis within a volume formed by the ball.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation of U.S. patent applicationSer. No. 16/893,431, filed Jun. 4, 2020, which is a continuation of U.S.patent application Ser. No. 15/415,669, filed Jan. 25, 2017, which is acontinuation of U.S. patent application Ser. No. 13/470,013, filed May11, 2012, now U.S. Pat. No. 9,585,669, which is a continuation of U.S.patent application Ser. No. 12/911,034, filed Oct. 25, 2010, now U.S.Pat. No. 9,039,726, which is a continuation of U.S. patent applicationSer. No. 12/427,620, filed Apr. 21, 2009, now U.S. Pat. No. 8,142,456,which claims the benefit of each of: U.S. Patent Application Ser. Nos.61/046,594 and 61/046,670, both filed Apr. 21, 2008; U.S. PatentApplication Ser. Nos. 61/083,957 and 61/083,961, both filed Jul. 28,2008; and U.S. Patent Application Ser. No. 61/145,097, filed Jan. 15,2009. Each of the foregoing applications is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present invention is directed to braid-balls suitable for aneurysmocclusion and/or parent vessel occlusion/sacrifice (e.g., in treatingneurovascular defects).

BACKGROUND

Mainstream clinical practice in endovascular treatment of intracranialaneurysms has changed little since the 1990's when vasoocclusive coiluse became widespread. Certainly, improved catheters and other auxiliarydevices (e.g., stents) have helped make coiling procedures safer and/ormore effective. However, the art in achieving adequate and appropriateaneurysm coil packing is best accomplished by the most highly skilledphysicians.

Where practicable, aneurysm exclusion by cover-type devices (e.g., asdescribed in U.S. patent application Ser. No. 12/397,123 to the assigneehereof) may be preferred. Certain other groups are attempting to shiftthe paradigm away from intra-aneurysm coil packing to achieveembolization via deployment of an extra-aneurysm flow disruptor/diverterstent in the parent vessel. These densely braided devices and/ormultiple braid devices layered upon one another are placed in the parentvessel across the neck of an aneurysm with the intent to alterhemodynamics so as to effect embolization.

These WALLSTENT-like devices are best suited for placement acrosssidewall aneurysms. Yet, terminal aneurysms (e.g., bifurcationaneurysms) are estimated by some to make-up between about 60 and 80% ofall aneurysm occurrences. By most optimistic count, only about 40% ofintracranial aneurysms can be treated using the referenced stent-likedevices.

Numerous other devices have been conceived in effort to address terminalaneurysms. Complicated and/or impracticable deployment is common tomany. Others simply serve as adjunctive to coils or liquid embolicagents. In these latter examples, procedures may become even morecomplicated and require even greater physician skill than a standardcoiling procedure.

A simpler, yet promising solution is proposed in PCT/US 2007/0076232 toDieck, et al. A braided/mesh conical member is described for divertingblood flow from the aneurysm neck. A base of the device is set insidethe aneurysm while a flow diverter portion extends into the parentvessel to direct blood flow toward adjacent side branches and away fromthe aneurysm. The implant may be positioned within the aneurysm as astand-alone device or be supported by a connected stent-like body.

U.S. Pat. Nos. 6,168,622 and 6,506,204 to Mazzochi, et al. discloseanother type of braided flow disruptor set at least partly within ananeurysm. A bulbous portion is adapted to fit within the aneurysm domeand is anchored on the outside by a neck-covering flap. Given the mannerin which bifurcation aneurysms often incorporate branch vessel anatomy,such a patch would often interfere with and/or “flap” free raisingsignificant issues of potentially pathological thrombus formation withinthe parent vessel.

SUMMARY OF THE INVENTION

Implants of the present invention address shortcomings of each of theabove-referenced devices. As such, the subject implants (as well astheir associated delivery systems) offer potential to advance the stateof the art in endovascular treatment of vascular malformations,including aneurysms.

The present invention is directed to wire braid ball implants foroccluding blood flow at endovascular sites. Delivery systems and methodsof making the balls are also described. The balls are useful fortreating neurovascular defects. One use is in intracranial aneurysmembolization/occlusion and another in parent vessel occlusion (PVO) orsacrifice.

Generally speaking, the subject vascular implants are braided devicesusing a combination of bio-stable materials selected from StainlessSteel, Cobalt Chromium, Nitinol, Titanium, Titanium-alloys, Zirconiumand Zirconium alloys, PET (or another suture material) and medical-gradeadhesive. The density of the device is paramount in applications wherethe braid itself is intended to affect blood flow, allowing thrombosiswithin a volume formed by the ball to occlude a site. As such, highdensity braid/mesh is typically required. Namely, braid having at leastabout 48 ends, typically set at about 90 degrees or greater, indiameters from about 4 to about 8 mm may be employed. At largerdiameters (e.g., about 6 mm to 12 mm or more), more wire ends (e.g.,common multiples of 64, 72, 96, 128, 144) may be employed in forming theballs. Still higher typical wire counts may be employed. Either one ofcommercially available 192 and 288 carrier standard braiders may beemployed. Moreover, 3-D braiding technology (such services are providedby 3Tex, Inc.) may be employed in forming the braid matrix from whichthe balls are formed. In addition, any combination of wire diameter,wire count, braid angle, and per-inch crossings can be used to makebraid in order to configure an embolic and blood flow occlusive devicedeemed appropriate for a particular vascular site.

A range of wire sizes or combination of wire sizes may be employed,typically ranging from about 0.0008 to about 0.0015 inch, and up toabout 0.003 inches depending on desired delivery profile (which istypically desired to be less than about 0.050 inches—at least forneurovascular indications—and more generally up to about 0.070 forperipheral PVO indications). A single braid tube may have all wires thesame diameter, or may have some wires of a slightly thicker diameter toimpart additional strength to the braid layer. For example, half thewires of a 96 wire tube (i.e., 48 ends) can be e.g. 0.001″ diameter andthe other half of the wires can be e.g. 0.0015″ diameter. In which case,the two wire sizes would typically be interlaced uniformly in making thebraid. The thicker wires impart greater strength to the braid withoutsignificantly increasing the device delivery profile, with the thinnerwires offering some strength while filling out the braid matrix density.

The wire is preferably NiTi alloy that is superelastic at bodytemperature. The metal may be a binary alloy or a ternary alloy toprovide additional radiopacity. Alternatively, radiopaque platinumfibers may be included in the braid, or the wire may comprise platinumor gold core Nitinol DFT. Otherwise, hubs, bands or wraps (preferablyPt) used to secure the braid wire (at either or both distal and proximalends, and also in between caps where appropriate) may serve as the soleradiopaque feature(s).

To improve implant wire corrosion resistance and/or biocompatibilityafter heat setting shape, the implants may be etched in “AYA” SulfamicAcid solution, then passivated in Nitric acid solution. Alternatively oradditionally, pre-etched and/or polished wire may be employed inbraiding the implant matrix. Shape setting the braid in the implantshape may be performed in an oven/furnace, a fluidized bath or salt pot.All such processing is within ken of those with ordinary skill in theart.

Especially after heatsetting the shape, the wire may be coated with anagent for promoting a desired biological effect. For example, wire canbe coated with a thrombogenic or an endothelization agent, or otheragent capable of promoting a desired biological process at the targetsite. The braid balls may also be partially or fully coated on theexterior (e.g., with coating such as urethane) to increase the occlusiveeffect of the ball, provided the coating does not cause the deliveryprofile of the final device to exceed allowed limits. Hydrogel coatingalso offers an appealing option, such as a hydrogel-based polymernetwork capable of entrapping therapeutic agents as described in U.S.Pat. No. 6,905,700 to Won et al.

Likewise, while the balls advantageously comprise Nitinol braid, thebraid may instead comprise polymer—especially high strengthbiodegradable polymer such as MX-2 (MAX-Prene), synthetic absorbablemonofilament (90/10 Glycolide/L-Lactide) and/or G-2 (Glycoprene),synthetic absorbable monofilament (Glycolide (PGA), ε-Caprolactone(PCL), Trimethylene Carbonate (TMC) Copolymer) that is heat set intoshape (e.g., at 110 degrees centigrade for an hour).

Deliverability of the subject implants to certain neurovascular sites(e.g., distal intercranial aneurysms) often requires that they becompressible to pass through a catheter sized for navigating the narrowand tortuous vessels of the brain. Standard neurovascular catheterssuitable for such use have 0.021″ and 0.027″ lumen diameters. Especiallyfor higher wire count balls 0.027″ ID (e.g., Cordis Mass Transit BostonScientific Renegade HI-FLO) or larger (e.g., 0.044″ ID Concentric MerciDistal Access Catheter) commercially available micro catheters may bepreferred. For devices adapted to address PVO indications in whichhigher wire counts and/or larger wire diameters are used to ensureanchoring, the implants may require 5 and/or 6 Fr guide catheters fordelivery.

In any of the configurations described, the devices may comprisehigh-density Nitinol braid that is folded/doubled-back upon itself andheatset to provide an open body having two adjacent layers forming aneven denser matrix to occlude blood flow. The folded-back (inverted oreverted) section may be closed to define a distal end of the devicewhere a radiopaque feature may be located. At the opposite side of theimplant, braid filaments are held in a hub including at least an outerband.

A port within the hub can receive component(s) of an optional detachablepusher. Alternatively, the implant can be deployed through a catheterusing a simple pusher. Braid filaments within the hub(s) may be weldedto each other and/or the band. Alternatively, the braid and hub(s) maybe secured using biocompatible adhesive.

In a relaxed state, the implants define an open, preferably rounded,volume. In a delivery catheter, they compress into a substantiallycylindrical body. When deployed at a treatment site, they expand to abutsurrounding tissue and occlude flow in a clinically relevant timeframe.

Use of a detachable pusher allows for deploying a device (e.g., in ananeurysm) and checking fit. Deployed in an aneurysm to occlude theaneurysm at its neck, the implant device largely assumes the shape ofthe aneurysm, with the proximal hub and closely adjacent braid materialoutside the neck. To achieve such fit, the implants are provided in arange of sizes. These may progress in 0.5 mm to 1 mm diameterincrements. For aneurysm treatment at bifurcations, it may also bedesirable if the ball (at least in its delivered configuration) assumesa tear-drop shape to assist in a flow-divider/diverter type function asdescribed in Dieck, et al., referenced above.

Should the selected implant not fit as desired, however, it can simplybe withdrawn back into the delivery catheter. If desired fit is achieved(with the first implant or a replacement) as confirmed by medicalimaging, the implant is released.

An electrolytically-releasable GDC-type joint can be used hold theimplant secure to the pusher until release. Details regarding suitableelectrolytic detachment systems can be appreciated and applied to thecurrent system as taught in U.S. Pat. No. 5,122,136 to Guglielmi andcontinuing applications thereof—all of which are herein incorporated byreference. Another electrically-powered detachment approach employs ameltable fiber or suture junction connecting the implant to the deliverypusher/guide. In such a system, a polymeric core may be configured withhelically wound conducting ribbons held to the core. Upon application ofvoltage, sufficient current is conveyed through the ribbons to a wirebridge connecting them. Heat generated along the bridge, optionallyNiChrome wire, severs the suture that is tied onto or running adjacentto the bridge in order to release the implant. Further details of asuitable suture-melt detachment systems are described in theincorporated provisional applications.

Yet, mechanical detachment systems may be more preferred. An aspect ofthe present invention involves pushers in which at least one memberprovides mechanical interference at/with the implant hub port toreleasably lock the implant onto the pusher. In one approach, a wire orribbon exiting an extension of the pusher threaded through the portproduces such interference until it is withdrawn. In another example, aplurality of wires/ribbons are received through the port. One or more(typically two or three) of these wires extend through a pusher catheterbody to a proximal handle interface. A final “anchor” wire receivedthrough the port may also extend to the handle. The anchor wire includesa head sized to exit the hub port only after the other “control” wiresare cleared therefrom. The head is preferably formed by laser or plasmaheating/melting. The handle provides a user interface to first removethe control wires, and then (optionally) also pull the final anchorwire.

To assist in implant recapture should it not be released, a smoothlead-in/trumpet shaped recapture profile may be provided between the huband main body of the implant. In another approach relevant in atwo-layer implant, no such profile is provided. Rather only the outer ofbraid layer is secured within the hub, and the inner layer “floats”. Inthis way, only the outer layer must be straightened relative to the hubto retrieve the ball within the catheter/sheath, with the inner layerriding along.

In order to permit such action, the braid matrix must remain stable andinterlocked. Accordingly, when feasible, a one-over-one braid patternwill be preferred. In addition, the braid should be trimmed adjacent thehub where the hub-secured braid is most dense. So configured, the outerbraid both serves as a guide and is of such density to prevent looseends of the inner layer from poking through. Whereas a floating-layertype ball implant would typically only be used for an aneurysmindication due to reduced radial strength, the recapture profile may beused on either an implant intended for aneurysm or PVO use.

Recapture features aside, when deployed in a vessel for use in parentvessel occlusion, the subject implant is “sausage” shaped. For suchpurposes, it may be desirable that the compressed length of the ball isminimized relative to its diameter. Proximal and/or distal ends of theball may be flattened or flatter (such that the ball is more “donut”shaped) for this purpose.

Oversizing the device relative to the vessel provides adequate radialforce to anchor its position against blood flow/pressure. To generatemore anchoring force within a vessel for a PVO-dedicated implant (i.e.,of a given deployed length), the ball may be formed in a shape having anelliptical cross-section. To offer further improved vessel anchoring, acylindrical waist may be incorporated in the shape. Edges formed willconcentrate stresses on the vessel wall in some cases to improveanchoring. Yet, the bulk shape allows the implant to work within a widerange of vessel sizes. Indeed, one size may fit a wide range of vesseldiameters (e.g., a 10 mm ball suitable for 3-5 mm vessels, etc.).

In either type of implant (i.e., aneurysm or PVO), an advantageousconstruction involves folding or doubling-back the braid duringmanufacture to produce a two-layer matrix. A medial crease or fold inthe braid is formed that is used in defining one end of the implant.

The fold may be pre-set in the braid or formed when fixturing the braidfor shape setting. In the former case, the bend is pre-set byheatsetting the braid when confined in a tight tubular shape (e.g., by acrimper or at least partially within a hypotube). In the latter case,the braid is tied with suture at a point, a form is inserted in the openend of the braid tube and the braid is stretched, or positioned, overthe form with the folded section under compression. When heated to setthe shape, the suture burns away as the compression force sets the foldat a minimal radius.

The fold itself proves useful in a number of ways. In one variation ofthe invention, the folded section provides an atraumatic end to theimplant. The folded section can be left open, or tied closed by asuture, wire (or other material) loop. If not radiopaque itself, the tiemay also hold a marker band (knotted, glued or crimped on). If such amarker is provided, it may advantageously be suspended adjacent thetop/distal end of the ball within the interior volume.

Either way, upon compression to a delivery profile, the implant bodybasically pivots (rather than bends) at the fold, thus minimizingin-catheter/sheath forces. This improves device trackability as well asdelivery and the ability to recapture if treatment with another sizedevice is desirable.

In a PVO-specific implant, a marker band can be held between braidlayers adjacent the medial fold. The band is securely captured and“hidden” without presenting edges or other features. As such, the distalend of the device offers a smooth delivery/tracking profile without needto otherwise secure the band.

Utilized in any such fashion (i.e., open, tied or banded), joints andother delivery profile-increasing features are avoided at one end of theball. As such, the fold offers constructional advantages (includingimproved manufacturability)—as well as reducing areas for failure whereends of the braid would otherwise need to be secured. Moreover, thedoubled-over tubular stock achieves excellent density while ensuringconsistent compression and shape-recovery performance since the layersare well matched. So-matched, they extend/foreshorten to substantiallyan equal degree when exiting and (re)entering the catheter.

One variation of the invention takes advantage of the matched braidlayers, and simply eliminates the fold by grinding or otherwise cuttingit away after heatsetting (and, optimally, braid hub securement).So-prepared, the implant becomes more radially compliant as may bedesirable for aneurysm treatment. And without any additional spacetaken-up by the bend in the filaments, the ball can be furthercompressed for delivery through the smallest microcatheters (for a givenbraid density) to achieve access to more distal treatment sites.

Another variation of the invention may or may not be constructed using afolded-over approach. To achieve higher braid densities without stackingup additional layers having to fit within the microcatheter lumen,additional “cap” structures can be instead incorporated in the implant.For delivery, these features neck-down or compress in series. Yet, uponexit from the microcatheter, they recover to a position adjacent themain body of the implant.

The ball body and cap portions of the implant are typically constructedfrom a continuous section of braid. Intermediate marker sections may beprovided between the elements. A hub including a delivery system port isprovided at the proximal end of the device.

The proximal caps of braid provide additional braid layers to the deviceat an end where occlusion of blood flow is critical. The proximal end ofa ball placed in an aneurysm contacts the opening and neck of theaneurysm. To achieve greater flow occlusion, the braid caps can besingle or double layer braid. One or more braid caps can be placed atthe proximal end of the ball (i.e., a braid ball can have up to threebraid caps, and more if feasible).

The braid caps do not function, and are not adapted to function, asanchors for the device. An anchor holds fast or checks motion of anobject attached to it. To anchor something is to fix or fasten, or affixfirmly an object. The balls implants are not anchored in the aneurysm orparent vessel using the braid caps. Rather, the braid caps are designedto either be adjacent the ball within an aneurysm or to fill only theneck region. In either case, the caps do not substantially engagevascular tissue adjacent the ball. They serve as occlusive elements thatenhance the ball's embolic potential.

As alluded to, two types of capped braid ball implants are provided.Caps adapted to fit only in the aneurysm neck are typically round(though they may be oval) and may be offered in a variety of sizes tofit different neck sizes just as the ball portion of the implant isoffered in different sizes. In other words, across a whole line ofimplants, each of the cap size and ball size parameters may be varied.

The caps adapted to fit in an aneurysm adjacent the ball portion of theimplant are larger and shaped to conform to the ball-shaped body. Theirdelivery requires either compressing the ball portion of the implantwithin the aneurysm and deploying the cap therein, or deploying the capoutside the aneurysm and pushing it into the aneurysm in a deployedstate.

Delivery of the devices with the neck-filling cap(s) or disk(s) isperformed substantially the same as braid balls without such feature(s)with the exception that the delivery catheter is withdrawn further toexpose the cap(s) or the catheter is stationed outside the aneurysm neck(vs. at the neck) and the implant extruded therefrom. Of course, somecombination of such activity may alternatively be employed.

In any case, if the desired fit is achieved, the implant is released.Otherwise, the implant is pulled into the delivery catheter from theproximal hub. The one or more caps compress to the linear profile of thedelivery/retrieval sheath, followed by the ball portion.

In yet another variation of the invention, a braid-ball is used inconjunction with a stent. The ball may be attached to a stent, with themdelivered together. Alternatively, a frame or cage may be provided atthe end of a stent into which the braid-ball is delivered after thestent is in place. In either case, the ball and/or frame may be sized tofill substantially all of an aneurysm or only fill the neck. Either way,the stent will serve as an anchor to prevent the ball from migrating.The frame-plus-ball solution offers certain advantages in terms ofstaged deliverability, whereas the ball-topped stent offers a one-shotsolution achievable in a single delivery. In each example, the stent maybe either self-expanding (e.g., comprising superelastic Nitinol) orballoon-expandable (e.g., comprising stainless steel and mounted on aPTCA-type balloon). Regardless, the braid-ball implant employed may beany one of those described in the present filing or thosecross-referenced above.

The present invention includes the subject devices, kits in which theyare included, methods of use and manufacture. A number of aspects ofsuch manufacture are discussed above. More detailed discussion ispresented in connection with the figures below.

BRIEF DESCRIPTION OF THE FIGURES

The figures provided herein are not necessarily drawn to scale, withsome components and features are exaggerated for clarity. Of these:

FIGS. 1A and 1B are side-sectional views illustrating braid ball implantvariations in bifurcation and side-wall aneurysm locations,respectively, in which a folded section in each implant provides anatraumatic tissue interface;

FIG. 2 is a blow-up view of the implant pictured in FIG. 1B;

FIGS. 3A-3C are perspective side views of a folded-section braid ball inprogressively larger sizes;

FIGS. 4A and 4B are side-sectional views illustrating proximal-flapbraid ball implant variations deployed within bifurcation aneurysmlocations;

FIG. 5A is a side view of a stent-anchored version of a braid ballimplant, FIG. 5B is a side view a stent with a cage for receipt of abraid ball implant;

FIG. 6 is a side view illustrating a folded-section braid ball implantin a PVO application;

FIG. 7 is a side-sectional view of the implant in FIG. 6 ;

FIGS. 8A and 8B are side-sectional views of an implant shown in stagesof manufacture;

FIG. 9 is a side sectional view of an implant in which the foldedsection is to be utilized at a proximal side of the device;

FIGS. 10A-10E are side views illustrating stages of a folded-sectionbraid ball implant manufacture;

FIGS. 11A and 11B are end views diagrammatically illustrating atechnique for presetting the shape of the implant fold;

FIGS. 12A and 12B are side sectional views illustrating folded-sectionbraid ball implants with associated tooling for setting their shape;

FIGS. 13A and 13B are partial side-sectional views illustratingalternate braid/band affixation approaches;

FIG. 14 is a partial side-sectional view illustrating a hub-gluingapproach;

FIG. 15 is a partial side view showing a hub-trimming approach;

FIG. 16 is a side-sectional view illustrating another folded-sectionbraid ball implant variation;

FIGS. 17A-17D are side views illustrating stages of the FIG. 16embodiment manufacture;

FIG. 18 is a side view of a delivery system variation suitable for usein the present invention;

FIG. 19A is a partial side-sectional view of a distal end of anotherdelivery system variation suitable for use in the present invention;

FIG. 19B is an end view from within the implant of the system shown inFIG. 19A;

FIGS. 20A-20F are partial perspective views of implant detachment with asystem constructed according to the approach shown in FIGS. 19A and 19B;

FIG. 21 is a perspective view providing an overview of a treatmentsystem according to the present invention;

FIG. 22 is a photograph taken from U.S. Provisional Patent Appl. No.61/046,670 (incorporated herein by reference) demonstrating actualreduction to practice of a single-layer braid ball device made accordingto the present invention;

FIGS. 23A and 23B are side-sectional views of the braid ball inisolation and in use, respectively;

FIG. 24 illustrates a suture-melt resistance heater pusher for implantdelivery; and

FIGS. 25A-25F illustrate a production path of one implant embodimentencompassed by the current invention.

Variations of the invention from the embodiments pictured arecontemplated. Accordingly, depiction of aspects and elements of theinvention in the figures is not intended to limit the scope of theinvention.

DETAILED DESCRIPTION

Various exemplary embodiments of the invention are described below.Reference is made to these examples in a non-limiting sense. They areprovided to illustrate more broadly applicable aspects of the presentinvention. Various changes may be made to the invention described andequivalents may be substituted without departing from the true spiritand scope of the invention. In addition, many modifications may be madeto adapt a particular situation, material, composition of matter,process, process act(s) or step(s) to the objective(s), spirit or scopeof the present invention. All such modifications are intended to bewithin the scope of the claims made herein.

Turning to FIG. 1A, it shows a first implant 20 according to the presentinvention. It is formed from tubular braid stock comprising a resilientmaterial such as Nitinol, that defines an open volume (generally round,spherical, ovular, heart-shaped, etc.) in an uncompressed/constrainedstate.

Implant 20 is set within an aneurysm sac 2 at a vascular bifurcation 4.It is delivered by access through the trunk vessel 6 (e.g., the basilarartery), preferably through a commercially available microcatheter (notshown) with a delivery system as detailed below.

The size of the implant may be selected to fill and extend somewhat outthe neck 10 of the aneurysm so the proximal end 22 of the device helpsdirect blood flow along the surface of the braid from which it isconstructed to the branch vessels 8. A distal end of the ball isdome-shaped adjacent a fold 24 in the braid resulting in a two-layer 26,28 (inner and outer layer, respectively) construction at least whereimpacted by flow at the neck 10 of the aneurysm. As shown, one or moreturns of a coil 30 (e.g., Pt wire) or a band (not shown) may provide adistal radiopaque feature to mark the location of the implant.

The fold 24 in the braid is set at a tighter radius in the implant 40shown in FIG. 1B. Here, implant 40 is received within a sidewallaneurysm 12 off of a vessel 14. A hub 42 of the implant is facing bloodfrom and directed along the line of vascular access and delivery.

As more easily seen in FIG. 2 , implant 40 includes a tie 44 closing anaperture 46 defined by the fold. A radiopaque (e.g., Pt) marker 48 isheld by the tie. Such a marker does not interfere with compression ofthe implant for delivery. Radiographic visibility of the proximal end ofthe ball may be achieved by virtue of the density of the braid comingtogether, alone, or a radiopaque (e.g., Pt) band 50 may be added.

Tie 44 may comprise any biocompatible material including StainlessSteel, Titanium, Nitinol (possibly wire that is martensitic at bodytemperature—commonly referred to as “muscle wire”), suture, etc. Anadvantage of utilizing wire is that it may simply be twisted to secureits position, along with the marker. In any case, the tie filamentshould be thin (e.g., about 0.0015 inch diameter or less) if aminimum-radius fold is desired.

Another salient feature of implant 40 concerns the region adjacent hub42. Specifically, a flared or trumpet-shaped recapture profile 52 is setin the braid to aid in device recapture into the delivery catheterthrough which the device is advanced. An access port 54 is providedwithin the hub. This port accepts a delivery system interface. Deliverysystem construction as well as further optional details of the implantare provided below.

Of course, FIG. 2 shows a ball in an unconstrained condition. When setwithin an aneurysm, the implant will instead substantially conform toits shape (e.g., as shown in FIG. 1A). Generally, the implant will beoversized somewhat to exert some small load on the aneurysm wall to helpmaintain a stable position of the ball. However, the ball may beintentionally undersized, especially in a side-wall application (e.g.,as shown in FIG. 1B) should it be desired that any hub feature is ableto turn with the ball to trail with the blood flow.

Depending on the desired fit, the implant selected by the physician mayturn out to be not exactly the right size upon delivery due tovariability of aneurysm morphology and/or limitations of medicalimaging. It is then that the recapture profile is most useful byfacilitating implant retrieval. The first implant can be discarded infavor of a second with a more appropriate size. FIGS. 3A-3C illustrateimplants 60, 62 and 64 in a gradation of sizes. Naturally, the sizinginterval may be varied. Likewise, the shape may be varied.

In the three examples provided, it is notable that a consistent poresize is maintained toward the center of the ball. Generally it will bedesirable to minimize overall pore size. However, the density of thebraid that can be achieved in braiding a given tube of braid stock islimited by its diameter and wire size. Accordingly, each of the threeballs shown is made of braid incorporating a different number of wiresor “ends”. For example, the first implant 60 may be produced fromfolded-over 72-end material braided over a 6 mm diameter mandrel, thesecond implant 62 made of folded over 96-end braid from an 8 mm mandrel,and the third implant 64 made of folded-over 144-end braid made on a 10mm mandrel. Alternately, the larger implants (i.e., those around 10 mmin diameter) may also be made of 96-end braid in order to maintain alower crossing profile. Specifically, 0.027 inch catheter crossingprofile can be achieved when using 96-end braid made of 0.001″ diameterwire. Likewise, at the smaller end of the range (e.g., around 5 mm indiameter) 64-end braid may instead be selected to achieve 0.021 inchcrossing profiles.

In any case, braid filaments are shown in pairs within theseimplants—one from each layer 26, 28. While the organization of the braidis often more random, the double/dual layer construction—onaverage—results in higher density than might be achieved with asingle-layer implant due to limitations on braid density for a givenstarting diameter of braid.

The implants 70, 72 shown in FIGS. 4A and 4B, respectively, may also bedual layer construction. In which case, they would share their distalconfiguration with the previous implants 20/40/60. As shown, they aresingle-layer devices in which the distal end takes the form of an insethub 74.

Either way, the implants include unique proximal-end configurations. Inaddition to a ball or bulbous portion 80, each implant includes a flap76 intended to improve its blood flow disruption potential. Flap 76included in implant 70 is intended for intra-aneurysmal use. To deliverit as shown, the ball or bulbous portion is first delivered into theaneurysm sac 2. Then, that portion of the device is compressed whilestill mounted to pusher 100 to deploy the flap section therein. Afterfinal positioning is achieved as shown in FIG. 4A, then the pusherlocking member(s) received within hub 42 are released. Finally, thepusher is withdrawn into the delivery catheter 110. To assist in thedelivery method, one or more additional radiopaque features (such as aband 50 at the proximal end of ball section 80) may be provided so thatdeployment can be visualized at each stage.

The implant in FIG. 4B requires no such complication in delivery.Because flap 76 is of a size selected only to fill the aneurysm neck, itcan be delivered straight-away. Still, intermediate radiopaque featuresmay be desirable to confirm appropriate fit and/or deployment.

As pictured, the ball-and-disk variation of the implant shown in FIG. 4Bmay only be applicable to smaller-neck aneurysms as compared to the FIG.4A “acorn” type variation. Generally, the size of the disc will not besignificantly larger than the parent/trunk vessel 6 diameter and/or thatof the bifurcation region 4. Otherwise, the vasculature will interferewith deployment. As such, the disk may be limited to about 2.5 to about5 mm in diameter.

While understood better in the context of the implant manufacture stepsbelow, flap 76 may be formed using a simple washer or plate over whichthe braid is heat set. Otherwise, the forming tool may be curved ordished so that flap 76 better follows the contour of the main implantbody.

Flap 76 in the FIG. 4A variation will typically be formed using aconcave/convex form in similar fashion. The size of this flap may vary.As shown, its outer extent is roughly the same diameter of the ballportion 80 of the device. It may be smaller and/or cover a lesser extentof the proximal side of implant 70. Generally, flap 76 will cover atleast about a third and as much as one-half of body 80. In this way,adequate neck coverage is better insured when employed to treatwide-neck aneurysms.

FIG. 5A is a side view of a stent-anchored version of a braid ballimplant. Stent 120 is sized to anchor in the trunk vessel in treating aterminal aneurysm. This way, the ball portion 122 may be sized only tofill the neck of the aneurysm instead of its entire volume. Such anapproach may be especially useful for less regularly shaped aneurysms.The device in FIG. 5B is used in a similar fashion, except that abraid-ball implant is introduced and held by a frame or cage 124, afterthe stent section is set in place.

The frame may comprise a plurality of individual wires 126 secured to ahub 128 of the stent at a proximal end and another hub or platten 130 atthe distal end. In another variation, the wires making up the frame arecut from the same tube as the stent cells and any included hub. They mayterminate at a distal end within a hub, be swaged within a radiopaqueband, welded together, secured by adhesive, or attached by some othermeans. In any case, they are typically (though not necessarily) attachedto form a closed frame. Still, an open frame is contemplated—especiallyone in which the wires hook backwards (i.e., proximally) to help “catch”the ball when emplaced.

These devices (i.e., those illustrated in FIGS. 5A and 5B) are deliveredemploying standard techniques, except that “anti-jump”/retrievalfeatures may be incorporated into the stent section. Regardless, atleast one row of stent cells 132 is provided in the stent to provide aminimum level of anchoring; however, as many as five or more may beemployed—with or without any special delivery anti-jump/controlfeatures.

While the stents advantageously include three support extensions 136 forthe ball or ball cage, more or fewer may be employed. However, the useof three offers the minimal stable structure available. And where theycome together, they operate much like a universal joint to helpend-mounted ball/frame successfully interface with the aneurysm to betreated.

FIG. 6 illustrates an altogether different use of the subject implants.Namely, an implant 140 is deployed in a vessel (vs. adjacent a vesselwithin an aneurysm) to occlude flow. As referenced above, for PVO usethe distal end of the ball may include a nub or nipple 142. Indeed, sucha feature is advantageous in a construction as illustrated in FIG. 7 .

In this side-sectional view, the braid matrix is shown inverted (oreverted) at fold 24. A band 144 is set between the inner and outer braidlayers. The band closes the end and servers as a marker (especially whenit comprises Pt). An adhesive compound 146 (e.g., LOCTITE 3311 or 4014)may be used to fill any residual lumen within the fold aperture. As withthe other implants (including those in FIGS. 4A and 4B) the implant mayinclude a recapture profile section 52 at its proximal end, adjacent thehub 42. Likewise, it may include a hub port 54.

Otherwise, both ends of the implant may be closed/plugged with anadhesive or otherwise. Without a delivery system access port, theimplant may be delivered using a simple pusher (vs. being fullyretrievable and/or repositionable). So-configured, no proximal hub isrequired either. Indeed, the braid may simply be trimmed and shape setto come together and/or be secured by welding, adhesive or otherwise atthe proximal end.

Another optional aspect of the invention is illustrated in FIGS. 8A and8B. Namely, a folded layer implant 140 is first formed without takingsteps to minimize the bend radius at the braid fold 24. While stillusable, it may instead be desired to trim off the folded layer toproduce a modified implant 140′ as shown in FIG. 8B. Doing so eliminatesthe bulk, and also changes the implants delivery properties as may bedesirable in certain circumstances. The implant becomes more radiallycompliant and able to fit a wider range of aneurysm sizes because ends142 of the braid can pass by one another rather than bottoming-out. Assuch, the same implant 140′ can fill a smaller volume withoutnecessarily extending from the neck of the aneurysm as indicated bydashed in FIG. 8B.

In any case, because of the original construction technique utilizingone tube of braid and folding it over to produce two layers, the(now-separated) layers are well matched to predictably expand andcontract. Moreover, once any profile-limiting bends are removed (e.g.,by cutting, grinding, etc.) the layers can be reconnected if theadjustability feature described above is not desired. A urethane coatinglayer 144 or other adhesive (advantageously including radiopaque Bariumor Tantalum powder) may be used locally to accomplish such actionwithout a resulting increase in delivery profile.

Still, maintaining the fold in an implant offers numerous advantages inother circumstances—especially when it is formed in such a manner thatminimizes wire bend radius/profile. Namely, implants including the foldmay offer better size integrity and radial force in circumstances whendesired, eliminate any loose fibers at an end of the implant withoutfurther processing (such as by polymer application), provide a pocketfor a marker and/or tie to suspend a marker, etc.

Moreover, it is to be recognized that the folded end of the implant willnot necessarily be set at the distal end of the device. Rather, thefolded section 24 may be utilized at a proximal side as shown in FIG. 9. And the aperture 46 formed by the folded section (when held by a ring,band or tie 150) provides a delivery system 110 interface. The oppositeend of the implant may have an inset hub (e.g., as illustrated in FIGS.4A and 4B) or terminate with trimmed ends 142 much like that shown inFIG. 8B (with or without incorporated polymer) or be otherwiseconfigured.

In any case, FIGS. 10A-10D illustrates one approach to constructing afolded-section implant in which the profile of the fold is minimized. Aswill be appreciated by those with skill in the art, elements of themethod may be applied to various of the implant configurations discussedherein.

In these figures, FIG. 10A shows a section of braid 200, tied withsuture 202 upon a mandrel 204. The tie is offset from where the braid iscut so that when the braid is inverted as shown in FIG. 10B, the outerlayer 28 extends past the inner layer 26. A loose fold 210 is developedand the braid surrounds the implant shaping form 212.

In FIG. 10C, the braid is stretched and secured by wrap 214 (typicallyPt or Stainless Steel wire) around the ball form 212. Compression forms216, 218 are also shown (held by fixturing as indicated by arrows).Fold-side form 216 compresses the fold to a minimum profile during heatsetting (e.g., for Nitinol braid at 550° C. for 5 minutes). In thisprocess, the original tie 202 (if made of suture) burns away removingany impediment for achieving a zero or near-zero radius bend at thefold. Opposite form 218 my define a sharp shoulder section (for whenthat end of the ball is to be trimmed and used as the distal end, in a“floating-layer” ball as described below, etc.) or shape a recaptureprofile into the braid.

After any such shape-setting, a device perform 220 is ready once theinternal form is finally removed as illustrated in FIG. 10D. During thisprocess, the ends of the braid are forced open and typically lose braidintegrity/engagement. So that such action does not adversely affect theimplant integrity, a “tail” 222 incorporated in the perform 220 shouldbe sufficiently long (i.e., often about 2 cm or more) so as to avoid anydamage from unraveled braid ends impacting the intended body 224 of theimplant.

If the implant is formed from braid that includes an oxide layer, theperform is next etched, then passivated. However, if pre-etched wire isemployed in braiding and any heatsetting performed in a salt pot, vacuumfurnace, or using other equipment to minimize oxide formation, theperform may simply be subject to Nitric acid passivation.

Even if additional intermediate process steps are employed, FIG. 10Eillustrates a manner in which a band 50 may be added in forming a hub.Specifically, after tying the outer layer 28 with a wrap 226, the bandmay be threaded over this section. Without the inner layer underneath,the tied section 228 fits within the band 50 such that the band can besized to tightly fit around both layers of braid (and an optionalmandrel 230—the utility of which is discussed below) when advanced to apoint adjacent the implant body 224.

An alternative approach to compression-forming the fold during performshaping to achieve a minimum radius bends in the braid wire is presentedin FIGS. 11A and 11B. These figures illustrate a technique forpresetting the shape of the implant fold. In FIG. 11A, wedges 240 of acrimper device (e.g., as available through Machine Solutions, Inc. andothers) receive braid 200 that is folded over to define a plurality ofbends. A mandrel 242 is advantageously set inside the braid. The mandrellimits compression of the braid tube, requiring the bend radius tightenwhen the aperture 244 formed by the wedges is closed as indicated inFIG. 11B. The shape of the fold is set by heat and/or a combination ofstrain and heat. The heat may be applied by a torch, within a furnaceor, advantageously, by running current though the mandrel. In anotherapproach, a multi-element chuck or collet type device is employed in asimilar fashion to the crimper wedges illustrated above.

So-shaped, the overall implant may be formed largely as described inconnection with FIGS. 10A-10D without the use of the suture tie orcompression form 216. Instead, a permanent fine-wire tie that remainsthroughout the process may be employed to close the folded end of theball. This tie can be installed simply by flipping back the folded braidto expose the bends. Alternatively, it can be threaded through andaround the bend folds with a needle and tied.

Pre-treating the fold or compression forming it during heatsetting thebulk of the implant is advantageous especially for those cases in whichthe region adjacent the fold is to be dome shaped. However, when anubbin is acceptable in the device design given its intended use (e.g.,PVO) FIGS. 12A and 12B illustrate another approach. Specifically, ahypotube 250 (or other shaped form including a pocket) is placed overthe braid where the braid is trapped between a band 50 and/or the bandand mandrel 204 as shown. In addition, as shown in FIG. 12B, a secondhypotube 252 (or surface in a form pocket) can abut the distal bendpoint 254 to further constrain the braid for precision shape setting.

As for setting the remaining shape of the implant or its perform 220,FIG. 12A illustrates the use of a proximal trumpet shaped form 256 toset a smooth recapture profile. In FIG. 12B, the proximal form 258 setsa tight or sharp radius. Such a shape may be desired to achieve higherradial force in the implant due to greater local bending strain.

The implant shown in FIG. 12B seeks to achieve improved anchoring overthat in FIG. 12A by virtue of the other noteworthy features illustratedin the drawings. Namely, the cylindrical band 260 shape set in theimplant along the otherwise ovular device shape produces edges 262 thatinteract with vascular tissue with increased local stress to improveanchoring.

Both implants still share a flattened/reduced aspect ratio relative thespherical ball implants previously pictured. Such an aspect ratio allowsfor greater oversize for anchoring the self-expanding implants in vesselfor a resulting length of device. This fact is advantageous given thatthe focal length of occlusion is often important in treatingneurovascular defects in order to inadvertently block adjacentperforator/branch vessels in PVO applications.

Whatever the form of the implant, when a hub is included to secure thebraid filaments, certain affixation challenges must be addressed. Thehub must be securely fastened to the braid and it may be necessary tominimize the length of the feature. FIGS. 13A and 13B are partialside-sectional views illustrating alternate braid/band affixationapproaches. In FIG. 13A, band 50 is set past a trim line for the braid.The small resulting tail 270 provides a surface across which glue 272can be applied. Once cured (e.g., by UV application) the adhesive isentrained in the braid and forms an edge 274 over which the band cannotpass. If glue is not used, then the braid may be melted with a laser tosimilarly form an interference feature for the band. Such laserapplication may weld the braid to an internal band 276 if one isemployed. The laser may be applied in a radial direction around thebraid, or axially across the trimmed face of the braid.

Especially when utilizing laser energy, an alternative approach asillustrated in FIG. 13B may be employed. Here, by applying laser energydirected axially across the edge of the band(s) and the face of thebraid, all of these may be welded together. Even if so-welded, theresulting face may be sealed with polymer adhesive 272.

FIG. 14 illustrates yet another approach to hub fixation. Here, wickingis relied upon for glue/adhesive penetration through the braid under theband to form a bond. A bead 280 of glue is applied to an exposed segmentof braid 200 adjacent the band 50. A non-stick (e.g., PTFE coated)mandrel 230 may be situated inside the braid to precisely define a lumenwithin the glue-impregnated braid. The lumen advantageously operates asa delivery system port. Once the adhesive is cured and the mandrel isremoved, a precisely-sized composite wall structure is produced.

The adhesive may be applied evenly around the braid by rotating theassembly as indicated. Other approaches may be utilized as well. In onesuch approach a plurality of optional access windows 282 may be includedin the band to receive and disperse adhesive. Adhesive is alsooptionally wicked away from the braid 200 by a paper card or absorptivefiber pad 284 (or removed by other means) so that any excess ofwicking/flowing adhesive utilized to ensure braid lumen coverage and/orband 50 adhesion does not interfere with the self-expanding action ofthe implant body 224.

Use of an inner band 276 is also optional. While it occupies space thatthe braid-and-glue only lumen conserves, including an inner band in thehub assembly 42 may sometimes be desirable for the detachment systeminterface.

Use of an adjunct hypotube 286 is also optional. This tube, however,offers a useful grip or handle on which to clamp for subsequenttrimming. Especially for such use, a thick-walled (e.g., about 0.005″ orgreater) tube may be desirable because of additional stability it willyield. As with the band which becomes part of the implant, hypotube 286may include one or more access windows 282 for adhesive application.

For trimming an implant perform 220 (however it is shaped), FIG. 15illustrates an approach that coordinates well with the hub affixationapproach illustrated in FIG. 14 . Specifically adjunct hypotube iscaptured in a fixture 290 mounted on a slide 292. Lateral adjustment maybe provided for in order to align a saw blade 294 (typically a0.004-0.010 inch diamond-coated wheel) with a gap 296 establishedbetween the band and hypotube 286 grip. Once aligned (the cut line maybe at the gap, or the band itself may be cut down) the implant istrimmed-off. To aid in handling, the implant may be at least partiallyconstrained in a sheath 298 as shown. A precision cut/trim allows for aband (as trimmed or initially installed) as short as about 0.010 inch inheight. A more conservative size (e.g., about 0.020 inch in height) mayhowever be desired to ensure braid capture and detachment systemrobustness.

After the cut is made, the hub length may be further reduced by grindingits face. After mandrel removal (also cut-off in the trimming procedure)and cleaning in an ultrasonic bath, the hub face may be sealed withadhesive.

Produced using any of the referenced hubbing techniques, another implantvariation 300 is illustrated in FIG. 16 . Additional steps unique to itsmanufacture are presented in FIGS. 17A-17D.

The implant differs from those discussed above in that it includes alayer of braid that is not secured at each end of the device. Rather,the inner layer 26 “floats”. Its presence augments implant density, butits fibers adjacent the hub 42 are not forced to bend when the ball iscompressed in a sheath for delivery and/or recapture. As such,relatively less force is required for recapture, even when the braid isbent at approximately 90 degrees upon exiting the hub (i.e., without theproximal end of the implant body 224 including a recapture profile inthe design).

To produce a ball with the inner braid ends 302 proximate to the hubwhere the density of the outer braid is highest and best able to preventindividual filaments from the inner layer poking through the braidmatrix, an elegant set of manufacturing steps are carried out.Specifically, after starting with an implant perform 220 as shown inFIG. 17A, the outer layer of braid is pulled or pushed off of theintended body 224 of the implant as shown in FIG. 17B. The inner layerof braid is trimmed as shown in FIG. 17C. Wire cutters, scissors orother means may be employed. Finally, the outer layer is returned to itsoriginal position as shown in FIG. 17D and the implant perform isfurther processed.

Such further process may include banding/hubbing, trimming and/or tyingthe fold aperture closed. However, such tying may advantageously beperformed prior to restoring the position of the outer braid while thefold 24 is exposed per FIG. 17B/17C.

Whatever techniques are employed in their construction, the implants areadvantageously mounted to a releasable pusher. Delivery system 308 inFIG. 18 is includes a hypotube shaft 312 with cut-out windows 314. Thewindow 314 adjacent the ball hub is critical, the other merelyadvantageous. A core member 316 (advantageously Nitinol ribbon) exitsthe proximal window 314 or cutout and re-enters at the second 314. Ashoulder/bumper 317 attached to the hypotube abuts a proximal end of thehub 50 to push the implant 40. Alternatively, an external sleeve (notshown) running to the length of the hypotube to a delivery system strainrelief 318 and/or hub 320 may be provided. To permit retracting theimplant into the delivery catheter (not shown), core member 316 engagesthe inner surface of the hub lumen (hidden) to retain the implant.

To allow release, the core member is withdrawn into hypotube 310clearing each of the windows 314 by pulling finger grip 322. At whichpoint, the hypotube may exit the hub port 54 by withdrawing the pusher.

Another detachable delivery system 330 is illustrated in FIGS. 19A and19B. It is a fully co-axial design in which control wires 332 are pulledto release interference of a head 334 mounted on an anchor wire 336otherwise unable to pass through a hub port or lumen 54. Because thewires are pulled straight out and only position the anchor wire head toensure interference (clearly illustrated in FIG. 19B) minimal effort isrequired. EPTFE coating over at least the control wires is also useful.

The control wires 332 may extend to or past the anchor wire head 334(the former case illustrated in FIG. 19A). Another option is to limitthe control wire length to that of any inner band 276 or overall hub 42height dimension (as illustrated in FIG. 19B). Note also: FIG. 19A showsa gap between a pusher sleeve 338 and implant hub 50. Thisrepresentation is for illustration purposes only.

In any case, each of the pusher sleeve lumen 340 and the implant hublumen/port 54 is preferably sized so that the wires (control wires 332and anchor wire 336) are received in a close-packed arrangement. In thismanner, the implant and pusher sleeve serve as a guide eliminatingloading difficulties associated with the wires becoming braided orentwined. Also for loading the system, the anchor wire is typicallytensioned to a very slight degree (prior to simple gluing into a handleor using a bias spring incorporated in the handle design) to ensure anygap between the implant and pusher is closed and remains closed in use.

FIGS. 20A-20F illustrate a variation of delivery system 330 is use. Thedistal end of the detachment system is shown with the hub 42 portion ofan implant. FIG. 20A shows the pusher interlock engaged. FIGS. 20B-20Dillustrate sequential withdrawal of the control wires 332. Anchor wire336 may also be individually withdrawn as shown in FIG. 20E. However, itmay instead by withdrawn with the detachment system sleeve 338. Indeed,it may be affixed to the sleeve. Still further, it is to be recognizedthat the control wires need not be pulled one at a time. They can beactuated together. In any case, complete implant separation isillustrated in FIG. 20F.

Finally, FIG. 21 presents an overview of a treatment system 340including an implant 342 and handle 334. Either one or both of these maybe constructed according to the teachings herein. The handle 334 shownincludes three knobs. Two knobs 344 are connected to control wires(hidden from view), and the last knob 346 to an anchor wire (hidden fromview). A removable locking cap 348 may be included in the handle designas well as a strain relief section 350. The catheter/pusher shaft 338may comprise a simple extrusion (e.g., PTFE, FEP, PEEK, etc.) or may beconstructed using conventional catheter construction techniques andinclude a liner, braid support and outer jacket (not shown). A loadingsheath 352 is typically provided over the pusher shaft. Advantageously,the loading sheath is splittable as is model shown.

After removal from sterile packaging (not shown), the implant is pulledinto the loading sheath 352. The loading sheath is received within thehub of the catheter to be used for implant delivery and the implant isadvanced into the catheter. Then, the implant may be advanced to anddeployed at a treatment site. Or it may be retrieved in exchange foranother size implant, else repositioned if desired prior to ultimatedetachment like that illustrated in FIGS. 20A-20F.

The subject methods may include each of the physician activitiesassociated with implant positioning and release. As such, methodologyimplicit to the positioning and deployment of an implant device formspart of the invention. Such methodology may include placing an implantwithin a brain aneurysm, or at parent vessel targeted for occlusion, orother applications. In some methods, the various acts of implantintroduction to an aneurysm or parent vessel are considered.

More particularly, a number of methods according to the presentinvention involve the manner in which the delivery system operates inreaching a treatment site, for example. Other methods concern the mannerin which the system is prepared for delivering an implant, for exampleattaching the braid ball to the delivery system. Any method herein maybe carried out in any order of the recited events which is logicallypossible, as well as in the recited order of events, or slightmodifications of those events or the event order.

Also, it is contemplated that any optional feature of the inventivevariations described may be set forth and claimed independently, or incombination with any one or more of the features described herein.Reference to a singular item, includes the possibility that there is aplurality of the same items present. More specifically, as used hereinand in the appended claims, the singular forms “a,” “an,” “said,” and“the” include plural referents unless specifically stated otherwise. Inother words, use of the articles allow for “at least one” of the subjectitem in the description above as well as the claims below. It is furthernoted that the claims may be drafted to exclude any optional element. Assuch, this statement is intended to serve as antecedent basis for use ofsuch exclusive terminology as “solely,” “only” and the like inconnection with the recitation of claim elements, or use of a “negative”limitation.

Without the use of such exclusive terminology, the term “comprising” inthe claims shall allow for the inclusion of any additional elementirrespective of whether a given number of elements are enumerated in theclaim, or the addition of a feature could be regarded as transformingthe nature of an element set forth in the claims. Except as specificallydefined herein, all technical and scientific terms used herein are to begiven as broad a commonly understood meaning as possible whilemaintaining claim validity.

The breadth of the present invention is not to be limited to theexamples provided and/or the subject specification, but rather only bythe scope of the claim language. Use of the term “invention” herein isnot intended to limit the scope of the claims in any manner. Rather itshould be recognized that the “invention” includes the many variationsexplicitly or implicitly described herein, including those variationsthat would be obvious to one of ordinary skill in the art upon readingthe present specification. Further, it is not intended that any sectionof this specification (e.g., summary, detailed description, abstract,field of the invention) be accorded special significance in describingthe invention relative to another or the claims. All references citedare incorporated by reference in their entirety. Although the foregoinginvention has been described in detail for purposes of clarity ofunderstanding, it is contemplated that certain modifications may bepracticed within the scope of the appended claims.

Especially for aneurysm treatment, but also for either one of theaforementioned treatments, the form of the ball is very important. Inparticular, the density of the device is paramount in applications wherebraid itself is intended to moderate or stop blood flow—allowingthrombosis within a volume formed by the ball.

According to the present invention, braid-ball type implants areprovided in braid of sufficient density to moderate blood flow withinthe volume of the implant. Upon thrombosis, flow thereto is stopped.Alternatively, a blood-barrier covering can be applied to thefilamentary structure to immediately stop blood flow into the vascularsite, in which the implant volume is set.

In either case, to form thrombosis within the volume of the ball, thefilaments of the braid matrix permit filling of the implant with bloodwhen emplaced at a vascular treatment site. This blood then thrombosesdue to the flow-disruption effect(s).

Unlike Nitinol tube-cut cages that may be suitable for (or assist) incoil retention, the ball devices are adapted to work alone—or incombination with each other to effect a complete treatment. As such,high density braid/mesh is typically required. Namely, braid having atleast about 48 ends, typically set at about 90 degrees or greater, indiameters from about 4 to about 8 mm may be employed. At largerdiameters (e.g., about 6 to 12 or more), more wire ends (e.g., 64, 72and upwards) may be employed in forming the balls.

Suitable braid for constructing the balls may be obtained from SecantMedical, Inc. Wire diameters may be in the range of about 0.001 to about0.003 inches, depending on desired delivery profile (which is typicallyless than about 0.050 inches). The braid forming the balls mayincorporate only one size wire, or may be formed with multiple sizes.

The wire is preferably superelastic NiTi alloy. The metal may be abinary alloy or a ternary alloy to provide additional radiopacity.Alternatively, radiopaque platinum fibers may be included in the braid,or the wire may comprise platinum or gold core Nitinol DFT. Otherwise,wraps or bands (preferably Pt) used to secure the braid wire may serveas the sole radiopaque feature(s).

In any case, the construction approaches described herein enableproducing these useful devices. Whether comprising braid alone, orincorporating some further blood-barrier covering (such as a thinurethane film as may be applied by Hantel, Inc. or others), the use ofbraid presents numerous challenges in managing the termination ofmultiple wires and in forming the desired structures.

Also included in the invention are detachable implant pushers thatutilize a resistance wire heater to thermally sever a suture associatedwith the implant to effect release. As distinguished from knownapproaches where an implant is retained by a loop connected back to adelivery system pusher that is withdrawn with the delivery system, thepresent invention contemplates a leave-behind tether.

Further details, variations, modification and optional features of theinvention may be appreciated by review of any of the incorporated patentapplications. However, the priority date and subject matter included inthe appended claims rely solely on the subject matter filed in U.S.Provisional Patent Application Nos. 61/046,670 and 61/046,594, theearliest patent applications (each filed Apr. 21, 2008) on which U.S.patent application Ser. No. 12/427,620 relies. Selected figures from the'670 and '594 application and all of text from the '594application—all—incorporated by reference in the parent applicationhereto is reproduced herein.

Implants

Referring to FIGS. 22-25F, a filamentary implant 402 is formed out ofbraid to treat vascular sites. Interwoven filaments 404 form a braidmatrix 406 that define a self-expandable occlusion device.

As single layer of the braid is provided in which ends of the braid aresecured and managed to provide an atraumatic interface. Specifically,ties 410 (as illustrated in FIG. 22 ) or bands 412 (as illustrated inFIGS. 23A and 23B) secure the ends 414 of the braid from which theimplant is constructed.

In the implant variation pictured, the expanded configuration defines anovoid or roughly spherical shell 418 that is permeable to blood. Thebraid defining the proximal and distal ends of the implant turns orcurves inward to a point where it is secured within the periphery of theshell.

The inversion of the braid provides recessed securement of the braidresulting in atraumatic ends of the implant. The braid filamentsoptionally extend beyond the securing/securement features in order todefine wire filament “tufts” 420 that will further promote thrombosis ofblood that enters the ball upon deployment within a patient'svasculature. However configured in regard to braid filament endsecurement and termination, inset ends of the braid (proximal and distalinsets 422/424, respectively) are demonstrated when the implant is in anexpanded state to fill an aneurysm 426 off of a vessel 428.

Delivery Systems

FIG. 24 illustrates a detachable catheter/pusher 430, optionally, foruse in the present invention. Generally, it includes a resistance wirebridge 432 across insulated conductors 434 (a typical construction).What is unique is that the conductor wires are twinned/twisted along alength of the delivery pusher shaft 438 as shown. This configurationalleviates bending bias/preference. Upon application of voltage, the tipthermally severs the polymer filament (e.g., suture 440) in contacttherewith. At least the suture portion is received within the implant402 (e.g., passing through a braid-securing band 412). The suture isretained in/with the implant upon actuation to release the implant bycutting through the suture with heat. A ball stop 442 that is tied tothe suture and retains the filament in/with the implant is alsoillustrated. Finally, pusher 430 is shown received within a typicalmicrocatheter 444 for vascular access, after passage therethough. Notealso, other advantageous delivery system are referenced and described inthe incorporated patent application.

Methods of Manufacture

Included in the invention is a method of manufacture including tying-offor otherwise securing a second end of a braid within an interior volumeof a ball where other approaches would be impracticable. The techniquemay be employed in creating the balls (be they spherical or ovaloid incross-section, etc.) out of one continuous section of braid. In sodoing, joints and other delivery profile-increasing features areavoided—as well as potential areas for failure. Accordingly, the subjectimplants are extremely robust and fully recoverable to their aneurysmalshape as is required when they are delivered through a catheter in lowprofile. Robust shape recovery is required in treatments targetingdistal vasculature, especially the tortuous neurovasculature encounteredin human brains.

A detailed example of one process path for implant formation isillustrated in FIGS. 25A-25F. As shown in FIG. 25F a final implant 402may begin as a section 450 of braided material. The tubular braid stockis secured. As shown, it is tied-off with a wire wrap 410. Such actiondevelops an inset region 424 for the implant body. An opposite end ofthe braid is then captured in a transfer tube 452. The tube is passedthrough the volume of the implant and secured with a second tie 410 atthe other side.

Additional refinement to the shape over that shown in FIG. 25E may beimparted within a shape-setting form 454. Mandrels 456 including stops458 received through the securement features may be employed to forceapposition of the ball to the shape of the form when pulled apart asindicated by arrows. After shape-setting in the form (as appropriate tothe selected material—e.g., as in heat setting superelastic Nitinol) themandrels are removed and the implant shaping is complete as shown inFIG. 25F. However, these additional forming steps are not necessarygiven that (in point of fact) the implant in FIG. 22 was producedwithout employing the same.

Methods of Use

Any one of the subject implants is delivered to a target site employingknown percutaneous catheter access techniques. The implant may besecured to a pusher (e.g., pusher 430) used to advance it through theaccess catheter (e.g., microcatheter 444). Upon emplacement at thetreatment site (e.g., cerebral aneurysm 426 as illustrated in FIG. 23A),the implant can be detached. With the exemplary system shown in FIG. 24, the suture 440 passing through the proximal end of the implant 402 issevered by melting it using a resistance heater. This retention/releasefiber remains in and with the implant.

We claim:
 1. A device for implantation within a cerebral aneurysm, thedevice comprising: a resilient mesh structure comprising a plurality ofbraided filaments, the mesh structure having a proximal regionconfigured to be positioned within the aneurysm cavity, over a neck ofthe aneurysm, and a distal region configured to be positioned within theaneurysm cavity, wherein the mesh structure has (a) a compressed statefor delivery through an elongated shaft, and (b) an expanded state inwhich the mesh structure has a width greater than a width of the meshstructure in the compressed state, and wherein the mesh structurecomprises an inner layer and an outer layer having respective proximalends wherein the inner layer transitions to the outer layer at a foldthat defines a distal end of the device; and a marker band disposed atthe proximal region of the mesh structure, wherein the marker bandsecures the proximal ends of the inner and outer layers relative to oneanother.
 2. The device of claim 1, wherein, in the expanded state, themesh structure is configured to self-expand towards a predeterminedshape in which a width of the mesh structure decreases proximallytowards the marker band.
 3. The device of claim 1, wherein the devicedoes not include a marker band at the distal region of the meshstructure.
 4. The device of claim 1, wherein the mesh structure isconfigured to conform to the aneurysm wall in the expanded state.
 5. Thedevice of claim 1, wherein at least some of the filaments comprise ashape-memory alloy.
 6. The device of claim 1, wherein at least some ofthe filaments comprise a superelastic material.
 7. The device of claim1, wherein at least some of the filaments are drawn-filled tubes havinga platinum core surrounded by an outer layer of Nitinol.
 8. The deviceof claim 1, wherein the proximal region of the mesh structure isrounded.
 9. The device of claim 1, wherein, when in the compressedstate, the device is configured to be delivered through a microcatheterhaving an inner diameter of 0.021 inches.
 10. The device of claim 1,wherein, when in the compressed state, the device is configured to bedelivered through a microcatheter having an inner diameter of 0.027inches.
 11. The device of claim 1, wherein the mesh structure isconfigured to self-expand when released from a delivery catheter. 12.The device of claim 1, wherein a distance between the inner layer andthe outer layer is substantially constant between the distal region andthe proximal region of the mesh structure.
 13. A device for implantationwithin a cerebral aneurysm, the device comprising: a resilient meshstructure having a proximal region configured to be positioned withinthe aneurysm cavity, over a neck of the aneurysm, and a distal regionconfigured to be positioned within the aneurysm cavity, wherein the meshstructure has (a) a compressed state for delivery through an elongatedshaft, and (b) an expanded state in which the mesh structure has a widthgreater than a width of the mesh structure in the compressed state; anda marker band positioned at the proximal region of the mesh structure,wherein the mesh structure comprises a braid that has been folded backon itself to form an inner layer and an outer layer, wherein the innerlayer transitions to the outer layer at a fold at a distal end of themesh structure, and wherein the braid comprises a plurality of braidedfilaments having first and second ends that are secured to one anotherat the marker band.
 14. The device of claim 13, wherein, in the expandedstate, the mesh structure is configured to self-expand towards apredetermined shape in which a width of the mesh structure decreasesproximally towards the marker band.
 15. The device of claim 13, whereinthe device does not include a marker band at the distal region of themesh structure.
 16. The device of claim 13, wherein the mesh structureis configured to conform to the aneurysm wall in the expanded state. 17.The device of claim 13, wherein at least some of the filaments aredrawn-filled tubes having a platinum core surrounded by an outer layerof Nitinol.
 18. The device of claim 13, wherein, when in the compressedstate, the device is configured to be delivered through a microcatheterhaving an inner diameter of 0.021 inches.
 19. The device of claim 13,wherein, when in the compressed state, the device is configured to bedelivered through a microcatheter having an inner diameter of 0.027inches.
 20. The device of claim 13, wherein a distance between the innerlayer and the outer layer is substantially constant between the distalregion and the proximal region of the mesh structure.